scholarly journals Investigation on the Fiber Orientation Distributions and Their Influence on the Mechanical Property of the Co-Injection Molding Products

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Chao-Tsai Huang ◽  
Xuan-Wei Chen ◽  
Wei-Wen Fu
Keyword(s):  
Injection Molding ◽  
Tensile Properties ◽  
Fiber Orientation ◽  
Flow Direction ◽  
Rapid Development ◽  
Injection System ◽  
Single Shot ◽  
Fiber Morphology ◽  
Orientation Tensor ◽  
Orientation Distributions

In recent years, due to the rapid development of industrial lightweight technology, composite materials based on fiber reinforced plastics (FRP) have been widely used in the industry. However, the environmental impact of the FRPs is higher each year. To overcome this impact, co-injection molding could be one of the good solutions. But how to make the suitable control on the skin/core ratio and how to manage the glass fiber orientation features are still significant challenges. In this study, we have applied both computer-aided engineering (CAE) simulation and experimental methods to investigate the fiber feature in a co-injection system. Specifically, the fiber orientation distributions and their influence on the tensile properties for the single-shot and co-injection molding have been discovered. Results show that based on the 60:40 of skin/core ratio and same materials, the tensile properties of the co-injection system, including tensile stress and modulus, are a little weaker than that of the single-shot system. This is due to the overall fiber orientation tensor at flow direction (A11) of the co-injection system being lower than that of the single-shot system. Moreover, to discover and verify the influence of the fiber orientation features, the fiber orientation distributions (FOD) of both the co-injection and single-shot systems have been observed using micro-computerized tomography (μ-CT) technology to scan the internal structures. The scanned images were further utilizing Avizo software to perform image analyses to rebuild the fiber structure. Specifically, the fiber orientation tensor at flow direction (A11) of the co-injection system is about 89% of that of the single-shot system in the testing conditions. This is because the co-injection part has lower tensile properties. Furthermore, the difference of the fiber orientation tensor at flow direction (A11) between the co-injection and the single-shot systems is further verified based on the fiber morphology of the μ-CT scanned image. The observed result is consistent with that of the FOD estimation using μ-CT scan plus image analysis.

scholarly journals Modeling and Simulation of Fiber Orientation in Injection Molding of Polymer Composites

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Jang Min Park ◽  
Seong Jin Park
Keyword(s):  
Finite Element ◽  
Injection Molding ◽  
Fiber Orientation ◽  
Flow Model ◽  
Three Dimensional ◽  
Coupled Analysis ◽  
Injection Molding Process ◽  
Molding Process ◽  
Orientation Tensor ◽  
Closure Approximations

We review the fundamental modeling and numerical simulation for a prediction of fiber orientation during injection molding process of polymer composite. In general, the simulation of fiber orientation involves coupled analysis of flow, temperature, moving free surface, and fiber kinematics. For the governing equation of the flow, Hele-Shaw flow model along with the generalized Newtonian constitutive model has been widely used. The kinematics of a group of fibers is described in terms of the second-order fiber orientation tensor. Folgar-Tucker model and recent fiber kinematics models such as a slow orientation model are discussed. Also various closure approximations are reviewed. Therefore, the coupled numerical methods are needed due to the above complex problems. We review several well-established methods such as a finite-element/finite-different hybrid scheme for Hele-Shaw flow model and a finite element method for a general three-dimensional flow model.

Integrated Prediction of Mechanical Behavior for the Non-Aligned Fiber Composites With Experimental Validation

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Bingyun Jiang ◽  
Chen Tian
Keyword(s):  
Injection Molding ◽  
Fiber Orientation ◽  
Mean Field ◽  
Transversely Isotropic ◽  
Integrated Approach ◽  
Mapping Method ◽  
Design Guidelines ◽  
Plastic Behavior ◽  
Micro Computed Tomography ◽  
Orientation Tensor

Abstract This paper aims to present an integrated multi-scale method for predicting the anisotropic and nonlinear elasto-plastic behavior of short glass fiber-reinforced polymer (GFRP) materials typically produced by injection molding. The proposed method combines injection molding and microstructure together, with considering the nonaligned fibers and their corresponding anisotropy, to semi-analytically estimate the local effective mechanical properties at every point of GFRP. Micro-computed tomography measurement and injection molding simulation are used to obtain the fiber orientation tensor. The two-step mean-field homogenization method is applied to calculate the mechanical behaviors of the PA66GF30 GFRP with distributed-orientation fibers based on the fiber orientation tensor. Reverse engineering is used to obtain the optimized parameters of J2-plasticity and Tsai-Hill three-dimensional transversely isotropic stain-based failure criterion. Moreover, the integral mapping method can complete the transformation of the fiber orientation tensor from injection simulation to structure simulation model. The proposed integrated approach with the optimized parameters is verified by predicting the ring samples’ behavior from injection plates. The results from this investigation are expected to provide some design guidelines for GFRP composites.

scholarly journals Numerical Simulation during Short-Shot Water-Assisted Injection Molding Based on the Overflow Cavity for Short-Glass Fiber-Reinforced Polypropylene

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhong Yu ◽  
He-Sheng Liu ◽  
Tang-Qing Kuang ◽  
Xing-Yuan Huang ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Injection Molding ◽  
Fiber Orientation ◽  
Delay Time ◽  
Flow Direction ◽  
Water Injection ◽  
Injection Pressure ◽  
Melt Flow ◽  
Melt Temperature ◽  
Short Shot ◽  
Main Cavity

Compared with water penetration condition of short-shot water-assisted injection molding with or without overflow cavity, it can be known from theory and common knowledge that short-shot water-assisted injection molding with overflow cavity has many advantages, such as it can save materials and energy. Then, the effects of melt short shot size, water injection delay time, melt temperature and water injection pressure on the penetration of water after penetration, and the orientation distribution of short fibers during water-assisted injection molding of the overflow cavity short-shot method were studied. It is found that the melt short shot size had the greatest influence on it, followed by water injection pressure, water injection delay time, and finally, melt temperature. With the increase of the melt short shot size, the thickness of the residual wall of the whole main cavity becomes thinner, the orientation of short fiber along the melt flow direction becomes higher, and the degree of fiber orientation changes becomes lower. In the front half of the main cavity, with the decrease of water injection pressure, the delay time of water injection, and the melt temperature, in the front part of the main cavity, the residual wall thickness becomes thinner, the fiber orientation along the melt flow direction becomes lower, and the fiber orientation changes degree becomes higher; in the latter half of the main cavity, the influence of the water penetration and the orientation distribution of short fibers along the melt flow direction are not significant.

scholarly journals Effect of Process Parameters on Short Fiber Orientation along the Melt Flow Direction in Water-Assisted Injection Molded Part

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Haiying Zhou ◽  
Hesheng Liu ◽  
Qingsong Jiang ◽  
Tangqing Kuang ◽  
Zhixin Chen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Water Temperature ◽  
Process Parameters ◽  
Fiber Orientation ◽  
Flow Direction ◽  
Water Pressure ◽  
Short Fiber ◽  
Response Surfaces ◽  
Melt Flow ◽  
Melt Temperature

The short fiber orientation (SFO) distribution in the water-assisted injection molding (WAIM) is more complicated than that in traditional injection molding due to the new process parameters. In this work, an improved fiber orientation tensor method was used to simulate the SFO in WAIM. The result was compared with the scanning electron micrograph, which was consistent with the experiments. The effect of six process parameters, including filling time, melt temperature, mold temperature, delay time, water pressure, and water temperature, on the SFO along the melt flow direction were studied through orthogonal experimental design, range analysis, and variance analysis. An artificial neural network was used to establish the nonlinear agent model between the process parameters and A11 representing the fiber orientation in melt flow direction. Results show that water pressure, melt temperature, and water temperature have significant effects on SFO. The three-dimensional (3D) response surfaces and contour plots show that the values of A11 decrease with the increase in water pressure and melt temperature and increase as the water temperature rises.

MOLDSTAR 90

Alloy Digest ◽  
2005 ◽  
Vol 54 (3) ◽  
Keyword(s):  
Compressive Strength ◽  
Injection Molding ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Blow Molding

Abstract MoldStar 90 is a high-performance beryllium-free copper alloy for the blow-molding and injection-molding industries. This datasheet provides information on composition, physical properties, hardness, tensile properties, and compressive strength. It also includes information on machining, joining, and surface treatment. Filing Code: CU-732. Producer or source: Performance Alloys.

MOLDSTAR 150

Alloy Digest ◽  
2005 ◽  
Vol 54 (2) ◽  
Keyword(s):  
Compressive Strength ◽  
Injection Molding ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Performance ◽  
Blow Molding

Abstract MoldStar 150 (formerly PAS 940) is a high performance copper alloy for the blow-molding and injection-molding industries. This datasheet provides information on composition, physical properties, tensile properties, and compressive strength. It also includes information on forming, machining, joining, and surface treatment. Filing Code: CU-729. Producer or source: Performance Alloys.

GRILON BT40X

Alloy Digest ◽  
1989 ◽  
Vol 38 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Injection Molding ◽  
Physical Properties ◽  
Tensile Properties ◽  
Unique Combination ◽  
High Rigidity

Abstract GRILON BT40X is an impact modified injection molding grade. It is an alloy between amorphous and semi-crystalline nylons. It offers a unique combination of toughness with high rigidity. This datasheet provides information on physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on casting. Filing Code: P-6. Producer or source: EMS-American Grilon Inc..

scholarly journals Warpage Reduction of Glass Fiber Reinforced Plastic Using Microcellular Foaming Process Applied Injection Molding

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 360 ◽  
Author(s):  
Hyun Kim ◽  
Joo Sohn ◽  
Youngjae Ryu ◽  
Shin Kim ◽  
Sung Cha
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Fiber Orientation ◽  
Mechanical And Thermal Properties ◽  
Micro Ct ◽  
Fiber Reinforced ◽  
Foaming Process ◽  
Microcellular Foaming ◽  
Glass Fiber Reinforced ◽  
The Impact

This study analyzes the fundamental principles and characteristics of the microcellular foaming process (MCP) to minimize warpage in glass fiber reinforced polymer (GFRP), which is typically worse than that of a solid polymer. In order to confirm the tendency for warpage and the improvement of this phenomenon according to the glass fiber content (GFC), two factors associated with the reduction of the shrinkage difference and the non-directionalized fiber orientation were set as variables. The shrinkage was measured in the flow direction and transverse direction, and it was confirmed that the shrinkage difference between these two directions is the cause of warpage of GFRP specimens. In addition, by applying the MCP to injection molding, it was confirmed that warpage was improved by reducing the shrinkage difference. To further confirm these results, the effects of cell formation on shrinkage and fiber orientation were investigated using scanning electron microscopy, micro-CT observation, and cell morphology analysis. The micro-CT observations revealed that the fiber orientation was non-directional for the MCP. Moreover, it was determined that the mechanical and thermal properties were improved, based on measurements of the impact strength, tensile strength, flexural strength, and deflection temperature for the MCP.

Effect of gas counter pressure on shrinkage and residual stress for injection molding process

2017 ◽  
Vol 37 (5) ◽  
pp. 505-520 ◽  
Author(s):  
Wen-Ren Jong ◽  
Shyh-Shin Hwang ◽  
Ming-Chieh Tsai ◽  
Chien-Chou Wu ◽  
Chi-Hung Kao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Injection Molding ◽  
Flow Direction ◽  
Injection Molding Process ◽  
Molding Process ◽  
Daily Lives ◽  
Counter Pressure ◽  
Packing Pressure ◽  
Sink Marks ◽  
Feedback Data

Abstract Plastic products are common in contemporary daily lives. In the plastics industry, the injection molding process is advantageous for features such as mass production and stable quality. The problem, however, is that the melt will be affected by the residual stress and shrinkage generated in the process of filling and cooling; hence, defects such as warping, deformation, and sink marks will occur. In order to reduce product deformation and shrinkage during the process of molding, the screw of the injection molding machine will start the packing stage when filling is completed, which continuously pushes the melt into the cavity, thus making up for product shrinkage and improving their appearance, quality, and strength. If the packing pressure is too high, however, the internal residual stress will increase accordingly. This study set out to apply gas counter pressure (GCP) in the injection molding process. By importing gas through the ends of the cavity, the melt was exposed to a melt front pressure, which, together with the packing pressure from the screw, is supposed to reduce product shrinkage. The aim was to investigate the impacts of GCP on the process parameters via the changes in machine feedback data, such as pressure and the remaining injection resin. This study also used a relatively thin plate-shaped product and measurements, such as the photoelastic effect and luminance meter, to probe into the impacts of GCP on product residual stress, while a relatively thick paper-clip-shaped product was used to see the impacts of GCP on shrinkage in thick parts. According to the experimental results, the addition of GCP resulted in increased filling volume, improvement of product weight and stability, and effective reduction of section shrinkage, which was most obvious at the point closest to the gas entrance. The shrinkage of the sections parallel and vertical to the flow direction was proved to be reduced by 32% and 16%, respectively. Moreover, observations made via the polarizing stress viewer and luminance meter showed that the internal residual stress of a product could be effectively reduced by a proper amount of GCP.

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